1. Field of the Invention
The present invention relates generally to switch routing in a telecommunications network. More particularly, the present invention relates to generating international switch routing according to a set of rules describing desired routing behavior using a description of a switch hierarchy.
2. Related Art
Long distance telephone service is provided via a hierarchical network of switches. Each switch within the hierarchy is responsible for providing a connection from each input to the switch to each output of the switch. The switches connect sources of telephone calls to their destination. A familiar example is where a caller in a first city, the source, desires to call a recipient in a second city, the destination. The switches in the hierarchy route the call from the caller to the intended recipient. The hierarchical organization of the network evolved in response to an increased number of subscribers, and demand for longer distance communications. The hierarchical system of switches provides a large amount of flexibility for routing calls between switches. Routing for domestic calls (within United States) has been automated to take advantage of the flexibility. In domestic routing, a computer automatically configures the routing of a network according to a specific set of routing rules.
Unfortunately, the situation is not so refined for the case of international call routing. This is due to an additional complexity in the switch hierarchy. The additional complexity results from gateway switches that are used to route international calls to an appropriate country. Every international call must be routed through a gateway switch if it cannot be directly routed to the country. Instances of direct routing are rare. Moreover, international calls provide multiple services, whereas conventional domestic calling only provides one service, voice. Different routing schemes are often required for the different services available with international calls.
Conventionally, configuring the switches to route international calls through a domestic network has been a manual process. The process entails reconfiguring domestic switches to identify and route international calls to a gateway switch. Because of the extensive amount of human intervention required to reconfigure the switches, the process is not only time consuming, but the potential for error is significant. As more countries are added to an international network, the manual process become even more cumbersome and consequently, the potential for error increases. Thus, what is required is an automatic routing system to automatically configure a network's routing to route international telephone calls through a domestic network to a gateway switch.